Saudi Arabia's state oil company is to be separated from the oil ministry as part of a wider restructuring.
The move was approved by the Supreme Economic Council, which was set up by King Salman this year to replace the Supreme Petroleum Council.
The new 10-member council is headed by the King's son, Prince Mohammed bin Salman.
He was appointed this week as the new deputy crown prince and is regarded as second in line to the throne.
On Wednesday, King Salman appointed Saudi Aramco's chief executive Khalid al-Falih as chairman of the company and health minister as part of a major political reshuffle. He has been replaced by Aramco senior vice-president Amin al-Nasser.
The main facets of Saudi oil policy - including maintaining the ability to stabilise markets by holding extensive reserves and a reluctance to interfere in the market for political reasons - are set by the top members of the ruling royal family.
There are no signs that the move will lead to any significant changes in the way that the world's top oil exporter and de facto Opec leader makes its decisions.
However, separating Aramco from the oil ministry is likely to be just the first step in a shake-up of the Saudi oil sector, according to analysts.
Mohammad al-Sabban, a former senior adviser to Saudi oil minister Ali al-Naimi, said: "This decision will bring more flexibility to the company to take decisions on a commercial basis, and keep full financial control."
The move could pave the way for a prince to be appointed as the next oil minister to replace 79-year-old Mr al-Naimi.
It had been thought that the royal family regarded the role of oil minister as so important that giving it to a prince could upset the kingdom's delicate balance of power and risk making oil policy hostage to bickering among the many princes.
Earlier this year, King Salman promoted his son, Prince Abdulaziz bin Salman - a long-serving member of Saudi Arabia's Opec delegation - to the role of deputy oil minister from assistant oil minister.
Ehsan ul-Haq, oil analyst at KBC Energy Economics, said it was highly likely that Prince Abdulaziz, a son of the King, could be appointed oil minister.
"[Falih's] shift to the health ministry suggests that he might not follow Naimi. His appointment to the chairman of Aramco, on the other hand, is only ceremonial," he said.
Aramco could not be reached for comment.